1. Technical Field
The present invention relates to a method and apparatus for data processing in general, and in particular to a method and apparatus for improving data communications. Still more particularly, the present invention relates to a method and apparatus for improving low I/O pin count interfaces for serial data communications.
2. Description of the Prior Art
Typically, serial data communication is carried out between a transmitter and a receiver, in which data transfer is carried out by transmitting data sequentially one bit at a time. Thus, a data-processing system having only a parallel data bus must translate parallel data of 8, 16 or 32 bits into a serial data stream when outputting the data to a serial communication port. The translation is generally carried out by software or by means of a serial transfer circuitry.
Under the prior art, it is almost impossible for a data-processing system to arbitrarily set the bit length for serial data communications. As such, valuable time is wasted during serial data communications because the serial data stream includes necessary information together with unnecessary information. For example, where data to be transmitted is only 6 bits, data corresponding to 2 bits is unnecessarily transmitted when the bit length is at 8 bits. Thus, time is wasted in transmitting the extra two bits of unnecessary information.
Furthermore, one of the many design considerations for a device is the "pin count" of the device. The pin count is the number of connection pins that connect the device (or the chip within the package of the device) to a bus or other signal lines. A reduction in the device pin count, even by only one pin, can have a significant positive impact in minimizing the cost of the device. Consequently, it would be desirable to provide a better apparatus for improving I/O pin interface having a minimum pin count, for serial data communications.